I've got a PID'd Quickmill Alexia.

From watching the PID display, I see that the boiler temperature drops quite a bit as I pull a shot. To quantify, when I start the shot, the boiler temp is at 221 (for example), but by the end of the shot the boiler temp is at 213, or so. Is that normal?

I don't know if that is normal, but my PIDed Alexia does it also.. But not as dramatic. I start at 224F and end at 220F by the end of the 30sec shot...

Anybody have any thoughts?

thanks!
Q

Mine does too. Currently my shots taste great...but if someone knows how to stabilize this temp change and have even better tasting shots, I'm all ears!

rickmonroe wrote:From watching the PID display, I see that the boiler temperature drops quite a bit as I pull a shot. To quantify, when I start the shot, the boiler temp is at 221 (for example), but by the end of the shot the boiler temp is at 213, or so. Is that normal?

There was only a 1 degree drop for the models we evaluated:



That said, the PID readout isn't meaningful once the extraction begins, though the thermocouple placement can make a significant difference in what it registers during the influx of cold water. In the kit designed by Jim Gallt (and sold by Chris Coffee), the SSR controlling the heating element is disabled when the pump is running. Unless there is an obvious taste defect or thermofilter reading showing a significant drop, I would attribute your readings to thermocouple placement, not actual temperature measured in the brewing chamber.

i was just looking at the same thing on my livia (no PID). when i pull a shot, my boiler pressure drops. i just attributed the pressure change to the change in water temp that was being fed from the cold reservoir through the hot boiler. does that make sense? i didn't really think it would have a noticeable effect, but its the only thing i could think of.

Thanks for all the comments. I was surprised to see the drop in temperature because the H-B review talked about Alexia's temperature stability. But it makes sense that the variation could be due to placement of the sensor.

I just received the Alexia yesterday, so I'm a bit nervous about it. When I first set it up, the heating element would not turn on for a few hours: the PID was displaying 30 degrees for boiler temperature and flashing "A2 Lo" alarm. A couple hours later, I switched the machine on again (hoping for a different result), and the heating element turned on.

itsallaroundyou wrote:does that make sense?

Your Livia is an HX espresso machine and the Alexia is a single boiler. Not surprisingly, the boiler temperature drops for both when cold water is introduced, but other than that, there's not much similarity between your espresso machine and Alex's (different boiler design, different grouphead design, significantly different thermal mass difference, etc.).

wooops! was thinking of the anita...sorry for the off topic post....

Now this is just a rough approximation because it does not take into account everything necessary but . . . knowing that the Alexia boiler is 0.75 litre plus the connecting lines and the grouphead.

Assume you have 32 ounces of water at a uniform temperature of 224 F, then remove 2 ounces of that 224 F water and add 2 ounces of 90 F water. The resulting average boiler water temp will be 216 F.

AUSTINrob wrote:Mine does too. Currently my shots taste great...but if someone knows how to stabilize this temp change and have even better tasting shots, I'm all ears!

They will all drop a little; mine is no different. However, if you are really concerned about the drop on the PID's display you can always flip on the steam switch to activate the heating element to regulate the temp (at least on the temp being displayed). I tend to do this at about the 4 second point after lifting the brew lever. Because I often make a cap, I leave the switch flipped to speed up the time needed to be ready to steam. Now as for taste difference, I can not distinguish a difference at all between a normal pull and one with the steam switch flipped, but then again you really shouldn't expect to given that the grouphead's temp will have more control over the temp of the water at the puck more so than the slight difference in the boiler. If this wasn't the case, the Alexia would be ready to brew within 10 minutes from a cold start. That big brewhead takes a bit of water above or below temp to really affect the temp at the puck.